Jamaican sprint sensation Usain Bolt overcame a terrible start to round off his season with a victory in 9.86sec in the 100m at the Diamond League meet on Friday.

Bolt's reaction time out of the blocks left him chasing St Kitts and Nevis veteran Kim Collins in front of a packed King Baudouin Stadium.

Fresh from claiming a second successive treble gold medal haul at the London Olympics, Bolt's pick-up was also slack, but his trademark strong drive phase allowed him to surge past the field.

The towering Jamaican even had enough room to ease up a full 10 metres from the line before quickly undoing the laces of his spikes and hurling them into the crowd.

Bolt's compatriots Nesta Carter (9.96) and Kemar Bailey Cole (9.97) finished in second and third positions.

"I'm just happy to have got through the season," said Bolt. "The key coming here was for the fans and just to get through injury free.

"Coming into this, I did a start yesterday and I said to my coach I'm so tired. I went through the motions, it was an okay race - I didn't lose.

"Mentally you've got to be in the game. The Olympics are a big stage and you don't want to make mistakes so you push yourself mentally and physically, and at the end of the season, the level goes down fast."

Bolt's training partner Yohan Blake, double sprint silver medallist in London, failed to upstage the master, also coached by Glen Mills.

Blake, who has not raced Bolt since the London Games, was eyeing Bolt's world record of 19.19sec in the 200m, having previously run 19.26sec on this track.

After nailing the bend, Blake faded slightly at the bell to win in 19.54sec, still the ninth fastest time in history.

"I came off the turn, felt no one beside me and couldn't push it," said Blake.

"Next year, I'll be coming back strong."

The stage had been set for Bolt and Blake's exploits by Olympic champion Aries Merritt of the United States, who clocked a stunning world record of 12.80sec to win the 110m hurdles.

Merritt smashed the previous record of 12.87sec set by Cuban Dayron Robles in June 2008 in Ostrava, Czech Republic.

"I was just trying to get under 13sec to cap off a good season," said Merritt.

"I'm finally living up to my potential after a lot of injuries... with people telling me to go and get a proper job."

The 27-year-old Merritt, who ran 12.92sec to win the Olympic title in London, bolted out of the blocks and by the fourth hurdle was ahead of the strong field.

Fellow American Jason Richardson finished second in 13.05sec, with Jamaican Hansle Parchment completing the podium in 13.14sec, to mirror the medal positions from the London Games last month.